Thanks to a series of discoveries made over the past year by the Curiosity and Opportunity rovers, planetary scientists are more confident than ever that the Martian surface probably had abundant water more than three billion years ago. And where there was water, there may also have been life.

But a new study published in the June 15 issue of the journal Icarus argues that liquid water was present on Mars as recently as 210 million years ago, in the form of huge lakes nestled inside glaciers on the flanks of the volcano Arsia Mons.

Such lakes "have been mentioned as a possibility before," said the study's lead author, Kathleen Scanlon, a graduate student